JP2008003488A - Method for detecting surface state of member to be detected and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the surface state of an intermediate transfer belt or the like and to exactly decide the necessity of exchange or maintenance thereof so as not to perform useless exchange or maintenance thereof. <P>SOLUTION: In the method for detecting the surface state of an image carrier in the image forming apparatus, polarized light is radiated to the surface of the image carrier 23, and reflected light therefrom is received by a first photoelectric sensor 102 through a first polarizing plate 105 having an axis of polarization in a first direction, and received by a second photoelectric sensor 103 through a second polarizing plate 106 having an axis of polarization in a second direction different from the first direction. Then, arithmetic operation is performed based on both of an output signal S1 from the first photoelectric sensor and an output signal S2 from the second photoelectric sensor, and the surface state of the image carrier 23 is detected based on the result of the arithmetic operation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for detecting a surface state of a member to be detected and an image forming apparatus. For example, in image forming apparatuses such as copiers, printers, MFPs, facsimiles, or complex machines of these, it is used to detect the deterioration state of the image carrier and other parts and determine the replacement time and maintenance time. The

  Conventionally, in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine, a multifunction machine, or a multi-function machine called MFP (Multi Function Peripherals), an electrostatic latent image formed on a photosensitive drum is used. Development is performed to form a toner image, the toner image is primarily transferred to an intermediate transfer belt, and then further transferred to a recording sheet, and then fixed, and image formation is performed. In a full-color image forming apparatus, a tandem type print engine in which image forming units for each color of YMCK are arranged in a row is often used in order to increase the image forming speed.

  In a conventional image forming apparatus, in order to determine image forming conditions in each color image forming unit, a toner pattern of each color with various image forming conditions is created on an opaque transfer belt, and the image is formed on an intermediate transfer belt. The amount of toner adhesion of these toner patterns is detected by the provided reflective photosensor.

An example of a method for detecting the toner adhesion amount is disclosed in Japanese Patent Application Laid-Open No. H10-228707. According to this, a light emitting element that irradiates non-polarized light to the image carrier to which the toner is attached, and a first light reception in which the P wave component of the light reflected from the image carrier passes through the first polarizing filter. Device, second light receiving device in which S wave component is transmitted through the second polarizing filter, and signal processing device for amplifying the first and second light receiving device outputs and outputting the difference as toner adhesion amount information It consists of.
JP2002-310901

  Now, for example, infrared light from a light emitting diode is applied to the toner pattern on the transfer belt through the polarizing plate. Then, when the toner pattern is color, most of the infrared light is reflected (see FIG. 9). In this case, the light reflected by the color toner pattern changes in the light vibration direction, that is, the polarization axis, with respect to the irradiation light. For this reason, it is possible to separate the light having the polarization axis different from the irradiation light and the same light by the polarizing plate of the light receiving unit, and detect them with two photodiodes. As a result, it is possible to detect the adhesion amount of the color toner with high sensitivity.

  However, in the case of black toner, most of infrared light is absorbed (see FIG. 9). Therefore, the reflection of infrared light is very small in the black toner pattern, and the adhesion amount of the black toner can be detected with high sensitivity by the same mechanism as in the case of color.

  By this method, the amount of toner pattern adhesion on the intermediate transfer belt is detected, and the image forming conditions such as the charging voltage, developing bias, and exposure amount of each color are controlled, so that an image with good image density and gradation is obtained. Can be output.

  However, if the intermediate transfer belt on which the toner image is formed is scratched or the number of printed sheets increases, the processing agent contained in the toner may adhere to the surface of the belt and enter a filming state. In this case, the toner adhesion amount detection characteristic by the sensor changes greatly from the normal case as shown in FIG. Therefore, control for optimizing the toner adhesion amount and resist correction control cannot be performed.

  As a result, the intermediate transfer belt needs to be replaced and maintained with a certain amount of margin. Therefore, even for an intermediate transfer belt that does not necessarily require replacement or maintenance, the unit must be replaced or maintained, which is useless. Labor and costs are incurred.

  The present invention has been made in view of the above-described problems, and detects the surface state of an intermediate transfer belt or the like to accurately determine the necessity of replacement or maintenance, so that unnecessary replacement or maintenance is not performed. It is an object of the present invention to provide a method and apparatus for achieving the above.

  The method according to the present invention irradiates the surface of a member to be detected with polarized light, and the reflected light is received by a first photoelectric sensor via a first polarizing plate having a polarization axis in a first direction. And received by the second photoelectric sensor through a second polarizing plate having a polarization axis in a second direction different from the first direction, and an output signal of the first photoelectric sensor and the second Calculation is performed based on both output signals of the photoelectric sensor, and the surface state of the detected member is detected based on the calculation result.

  The method according to the present invention is also a method for detecting the surface state of the image carrier in the image forming apparatus, wherein the surface of the image carrier is irradiated with polarized light, and the reflected light is irradiated in the first direction. Light is received by the first photoelectric sensor through a first polarizing plate having a polarization axis, and second through a second polarizing plate having a polarization axis in a second direction different from the first direction. Light is received by a photoelectric sensor, a calculation is performed based on both the output signal of the first photoelectric sensor and the output signal of the second photoelectric sensor, and the surface state of the image carrier is detected based on the calculation result. .

  Preferably, the surface state of the image carrier is detected based on the calculation result, thereby determining the deterioration state of the image carrier.

  Further, the necessity of replacement of the image carrier or the necessity of maintenance is determined according to the determination of the deterioration state.

  Further, when it is determined that the image carrier needs to be replaced or maintained, the image carrier is not damaged until the image carrier is replaced or maintained. To set safe mode.

  The apparatus according to the present invention includes a light emitting unit that irradiates the surface of the detection member with polarized light, and reflects light reflected by the surface of the detection member with the polarization axis in the first direction. A first photoelectric sensor that receives light through a first polarizing plate, and a second photoelectric sensor that receives the reflected light through a second polarizing plate having a polarization axis in a second direction different from the first direction. 2 photoelectric sensors and a calculation based on both the output signal of the first photoelectric sensor and the output signal of the second photoelectric sensor, and the surface state of the detected member is determined based on the calculation result. And a determination unit.

  According to the present invention, the surface state of the intermediate transfer belt or the like can be detected to accurately determine the necessity of replacement or maintenance, and unnecessary replacement or maintenance can be prevented.

  1 is a diagram showing a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention, FIG. 2 is a diagram showing an arrangement state of an IDC sensor 33, and FIG. 3 is detecting a resist pattern by the IDC sensor 33. FIG. 4 is a block diagram showing an example of a functional configuration for detecting the surface state of the intermediate transfer belt 23 by the IDC sensor 33. FIG. 5 shows a P wave according to the surface state of the intermediate transfer belt 23. FIG. 6 is a diagram showing how the S wave ratio changes, FIG. 6 is a diagram showing how the detection characteristics of the IDC sensor 33 change according to the surface state of the intermediate transfer belt 23, and FIG. 7 is a usage condition of the image forming apparatus 1. FIG. 8 is a graph showing the relationship between the amount of adhering toner and the detection characteristics of P waves, and FIG. 9 is a graph showing the spectral reflectance characteristics of toner of each color. FIG.

  In FIG. 1, an image forming apparatus 1 is a digital multi-function peripheral or printer using an electrophotographic system, and has a built-in tandem print engine.

  That is, the image forming apparatus 1 has Y (yellow), M (magenta), C (cyan), and K (black) image forming units 24Y, M, C, and K arranged in a row in a tandem format. Yes. Each of the image forming units 24Y, 24M, 24C, 24K exposes the surface of the photosensitive drum 41 in accordance with the photosensitive drum 41, the charging charger 42 for uniformly charging the surface of the photosensitive drum 41, and the image data of each color. Thus, the exposure unit 43 that forms an electrostatic latent image, the developing unit 44 that develops the electrostatic latent image with toner of each color to form a toner image, and the photosensitive drums 41 across the intermediate transfer belt 23. The transfer roller 22 disposed at a position, a cleaner 45 that collects and cleans toner remaining on the surface of the photosensitive drum 41, and the like.

  In the present specification and drawings, the symbols corresponding to the colors Y, M, C, and K may be suffixed with the symbols Y, M, C, and K, respectively.

  The intermediate transfer belt 23 is stretched between the rollers 25 and 26 so as to be along the upper portions of the photosensitive drums 41Y, 41M, 41C, and 41K, and travels in the direction of the arrow M1 in FIG. The transfer rollers 22Y, 22M, 22C, and 22K are in contact with the photosensitive drums 41Y, 41M, 41C, and 41K, respectively, and between the photosensitive drums 41Y, 41M, 41C, and 41K. The transfer belt 23 is movable between a separation position where the transfer belt 23 is separated (also referred to as separation or retraction). The intermediate transfer belt 23 is pressed against the photosensitive drums 41 </ b> Y, 41 </ b> Y, 41 </ b> M, 41 </ b> K, and the toner image on the photosensitive drum 41 is primarily transferred to the intermediate transfer belt 23.

  The toner image primarily transferred to the intermediate transfer belt 23 is secondarily transferred by the secondary transfer roller 28 onto the recording paper PA, which is a transfer material fed from the paper feed cassette 27. Thereafter, the recording paper PA is fixed by the fixing unit 29 and discharged to the paper discharge tray 30. The position of the secondary transfer roller 28 is switched between a pressure contact state and a separation state with respect to the intermediate transfer belt 23 by various types or configurations of contact / separation driving devices (contact / separation mechanisms). A belt cleaner 31 and a waste toner box 32 are provided in the vicinity of the roller 26.

  At a position close to the roller 25, an optical IDC sensor (density detection sensor) 33, which is a density detection means for detecting the density of the toner image on the intermediate transfer belt 23, is provided. That is, the IDC sensor 33 irradiates the surface of the intermediate transfer belt 23 with light, and detects the amount of light that is reflected and returned. It is also possible to control the light emission amount of the IDC sensor 33.

  When the density of the toner image on the intermediate transfer belt 23 is low, that is, when the amount of toner on the intermediate transfer belt 23 is low, the amount of light reflected by the intermediate transfer belt 23 is returned and the amount of light increases, and when the density of the toner image is high, that is, the toner. When there is a large amount of light, the light is blocked by the toner and the amount of reflected light decreases. In this way, the IDC sensor 33 confirms the state of the surface of the intermediate transfer belt 23. Based on the density of the toner image detected by the IDC sensor 33, image adjustment is performed by controlling the amount of light by the exposure unit 43 and developing conditions in the developing unit 44. Actually, the density of each pattern (toner patch) of Y, M, C, and K created for image adjustment is detected.

  In the present embodiment, the IDC sensor 33 detects the toner image density as described above, detects the surface state of the intermediate transfer belt 23, detects the deterioration state of the intermediate transfer belt 23, and Determine the need for replacement or maintenance. Details will be described later.

  In the present embodiment, the IDC sensors 33 are provided at two locations, but may be one location or three or more locations. Also, various positions or methods other than those described here may be adopted as the attachment position and attachment method of the IDC sensor 33.

  The control unit 21 includes a CPU 211, a memory 212, a control circuit 213, a communication interface 214, a magnetic storage device 215, and the like. The control unit 21 performs image processing on image data and controls the operation of each unit of the image forming apparatus 1. To do.

  The image forming means or the image forming method, the configuration or structure of each part, etc. in the image forming apparatus 1 are not limited to the examples described above. Further, the image forming apparatus 1 may be a monochrome / color copying machine, a printer, a facsimile, or a complex machine thereof.

  As shown in FIG. 2 to FIG. 4, the IDC sensor 33 includes a light emitting diode 101 as a light emitting element, photodiodes 102 and 103 as light receiving elements, a P wave polarizing plate 104 for irradiation, and a P wave for receiving light. Polarizing plate 105 and S-wave polarizing plate 106 for receiving light.

  The light emitting diode 101 emits infrared light or visible light having an intensity corresponding to the input current. The light emitted from the light emitting diode 101 is irradiated from the oblique direction onto the surface of the intermediate transfer belt 23 via the polarizing plate 104. Therefore, the irradiation light to the intermediate transfer belt 23 is light polarized by the polarizing plate 104, and is a P wave in this embodiment.

  The irradiated P wave is reflected by the surface of the intermediate transfer belt 23, the toner adhered thereto, or the toner pattern formed thereon. At this time, the polarization axis of the irradiation light changes according to the characteristics of the reflecting surface.

  That is, when the light is reflected by a beautiful mirror surface, the polarization axis does not change, and the reflected light is the same P wave as the irradiated light. However, when the surface is rough and there are scratches or irregularities, or when toner adheres to the surface, the polarization axis of the irradiation light is disturbed and becomes random. In other words, the rougher the reflection surface, the more the reflected light is randomly polarized in various directions, and as a result, the P wave and the S wave in the reflected light approach almost the same amount.

  Such reflected light is incident on the photodiodes 102 and 103 via the P-wave polarizing plate 105 or the S-wave polarizing plate 106. Therefore, the photodiodes 102 and 103 respectively receive the P wave component and the S wave component of the reflected light from the surface of the intermediate transfer belt 23, and output the output signals S1 and S2 corresponding to the respective light amounts. Output.

  The light emitting diode 101 and the polarizing plate 104 constitute the light emitting portion of the present invention, the photodiode 102 and the polarizing plate 105 constitute the first photoelectric sensor of the present invention, and the photodiode 103 and the polarizing plate 106 constitute the present invention. The second photoelectric sensor is configured.

  In FIG. 4, in order to detect the surface state and perform processing operations related thereto, the control unit 21 includes an amplification unit 111, 112, a calculation unit 113, a surface state determination unit 114, a safe mode setting unit 115, and a processing unit 116. Etc. are provided.

  The amplifying units 111 and 112 amplify the output signals S1 and S2 from the photodiodes 102 and 103.

  The calculation unit 113 performs calculation on the output signals S1 and S2 output from the amplification units 111 and 112. For example, the difference between the two output signals S1 and S2 is obtained.

  The surface state determination unit 114 performs a calculation based on both the output signals S1 and S2 from the two photodiodes 102 and 103, and determines the surface state of the intermediate transfer belt 23 based on the calculation result.

  When it is determined that the intermediate transfer belt 23 or the like needs to be replaced or maintenance is required, the safe mode setting unit 115 damages the image carrier or the like until the replacement or maintenance is performed. Set safe mode not to give.

  The processing unit 116 performs necessary processing based on a command from the surface state determination unit 114 or the safe mode setting unit 115, and displays necessary information on the operation panel. Further, the amount of light emitted from the light emitting diode 101 is controlled by adjusting the variable resistor VR1.

  Such a calculation unit 113, surface state determination unit 114, safe mode setting unit 115, and processing unit 116 may be realized by causing the CPU 211 to execute an appropriate program, for example.

  Next, a control operation using such an IDC sensor 33 will be described. First, image adjustment control will be described.

  First, for example, the light reflected by the surface of the intermediate transfer belt 23 remains a P wave without changing the polarization axis when the surface is clean, so the light passes through the P wave polarizing plate 105. The light enters the photodiode 102 and becomes an output signal S1. The amount of light incident on the photodiode 103 is almost zero. That is, the output signal S1 is maximum, but the output signal S2 is minimum and almost zero. On the other hand, when a high-density toner pattern is formed on the surface of the intermediate transfer belt 23, the P wave and the S wave of the reflected light have the same amount, and the output signal S1 and the output signal S2 are It is about the same size. If the density of the toner pattern is lowered, the amount of light directly reflected on the surface of the intermediate transfer belt 23 increases, so that the S wave decreases accordingly.

  Accordingly, when the difference (S1 -S2) between the output signal S1 and the output signal S2 is obtained, only the amount of light directly reflected by the surface of the intermediate transfer belt 23 can be extracted. Thereby, the shielding state by the toner on the intermediate transfer belt 23 can be detected as the toner adhesion amount. Such processing is performed in the surface state determination unit 114, but this is not particular. Based on the detection result, the charging voltage of the photosensitive drum 41, the developing bias voltage, the light amount of the exposure LED, and the like are adjusted.

  The toner pattern may be in any form such as a halftone pattern, a dot pattern (halftone dot), a screen pattern, or a solid pattern. Further, the image carrier to be subjected to density control is not limited to the intermediate transfer belt 23 as described above, and may be a drum shape, a roller shape, or the like as long as the toner images are superimposed. . Further, the image carrier may be the photosensitive drum 41 or other members.

  Next, in order to adjust the color registration error of each color, as shown in FIG. 3, a resist pattern is created on the intermediate transfer belt 23, and the writing position of the resist pattern for each color is detected by the IDC sensor 33. That is, the light from the light emitting diode 101 is applied to the toner on the intermediate transfer belt 23 through the polarizing plate 104. Similarly to the case of detecting the toner adhesion amount described above, the output signal S1 due to the reflected light incident on the P-wave photodiode 102, that is, the directly reflected light on the surface of the intermediate transfer belt 23. And the P wave component of the reflected light from the toner, and only the output signal S1 is stored in the memory. Using the data of the output signal S1 stored in the memory, the writing position can be calculated from the barycentric position of each color resist pattern. Based on the calculated result, adjustments such as a write timing correction to the exposure LED of each color for exposing the photosensitive drum 41, an image data position correction, and an exposure portion correction are performed. As the control for these adjustments, a known color misregistration correction control can be used.

  Next, a method for detecting the surface state of the intermediate transfer belt 23 will be described.

  As shown in FIG. 5A, when the surface state of the intermediate transfer belt 23 is fine, the irradiated P-wave light is substantially specularly reflected, so that the P-wave photodiode 102 is used as it is. Is incident on. At this time, since the S-wave component is very small, very little light is incident on the S-wave photodiode 103.

  However, as shown in FIG. 5B, when there are scratches or filming on the surface of the intermediate transfer belt 23, the diffuse reflection component at the time of reflection is larger than in the fine state, and the S wave The light incident on the photodiode 103 increases.

  Therefore, the surface state of the intermediate transfer belt 23 can be detected from the amount of change between the P wave component and the S wave component in the reflected light from the surface of the intermediate transfer belt 23. In this way, the calculation is performed on the output signal S1 and the output signal S2, and the surface state of the intermediate transfer belt 23 is detected based on the calculation result.

In other words, the surface state of the intermediate transfer belt 23 is detected by the IDC sensor 33 in a state where the toner is not attached to the intermediate transfer belt 23. For example, the surface state of the intermediate transfer belt 23 is determined to be normal in any of the following cases.
(1) The P-wave output signal S1 exceeds a predetermined value TH1.
(2) The S-wave output signal S2 is equal to or less than a predetermined value TH2.
(3) The difference (S1-S2) between the P-wave output signal S1 and the S-wave output signal S2 exceeds a predetermined value TH3.
(4) The ratio (S1 / S2) between the P-wave output signal S1 and the S-wave output signal S2 exceeds a predetermined value TH4.
(5) The ratio (S2 / S1) of the S-wave output signal S2 to the P-wave output signal S1 is equal to or less than a predetermined value TH5.

Further, in cases other than the case where it is determined to be normal by any one of (1) to (5) above, or for example, in the following case, it is determined that the surface state of the intermediate transfer belt 23 is in a deteriorated state.
(6) The P-wave output signal S1 is equal to or less than a predetermined value TH6.
(7) The S-wave output signal S2 exceeds the predetermined value TH7.
(8) The difference (S1-S2) between the P-wave output signal S1 and the S-wave output signal S2 is equal to or less than a predetermined value TH8.
(9) The ratio (S1 / S2) between the P-wave output signal S1 and the S-wave output signal S2 is equal to or less than a predetermined value TH9.
(10) The ratio (S2 / S1) of the S-wave output signal S2 to the P-wave output signal S1 exceeds a predetermined value TH10.

  When it is determined that the intermediate transfer belt 23 is in a deteriorated state, a message to that effect is displayed on the operation panel or the like. Further, when it is determined that it is in a deteriorated state, it may be determined that there is a need to replace the intermediate transfer belt 23, or it may be determined that there is a need for maintenance. In this case, a message to that effect is displayed on the operation panel or the like, and the service man is urged to replace or maintain the intermediate transfer belt 23.

  Further, when it is determined that the state is deteriorated, a time when replacement or maintenance of the intermediate transfer belt 23 is necessary may be calculated and displayed on an operation panel or the like. Such a period may be calculated including data on the frequency of use of the image forming apparatus 1 or read from a table stored in the memory.

  For the determination described above, each predetermined value TH may be set to an appropriate value. By changing the predetermined value TH variously, the contents of the judgment can be made different. For example, the predetermined value TH may be made different in determining whether it is in a deteriorated state, determining that replacement or maintenance is necessary, and calculating a time when replacement or maintenance is required. In calculating the time when replacement or maintenance is necessary, the time when replacement or maintenance is required may be predicted by variously changing the predetermined value TH.

  As described above, scratches and surface states of parts such as an image carrier are detected by a plurality of light receiving units provided with polarizing plates 105 and 106, and based on the results, the necessity of replacement or maintenance is accurately determined. In addition, it is possible to determine the replacement time, maintenance time, etc., and to accurately determine the life of the parts. Thereby, useless parts replacement can be avoided.

  Next, another example of the method for detecting the surface state of the intermediate transfer belt 23 will be described.

  FIG. 7 shows changes over time in the amount of light emitted from the light emitting diode 101 so that the photodiodes 102 and 103 can obtain a constant amount of received light. This time-dependent change data is stored in a memory.

  When the image forming apparatus 1 is used, the amount of light reflected from the photodiodes 102 and 103 (output signal) at an initial stage and at least two timings, ie, when a predetermined time elapses or when a predetermined number of sheets are printed. The calculation is performed based on S1, S2), and the surface state of the intermediate transfer belt 23 is detected based on the calculation result.

  For example, in a state where the surface of the intermediate transfer belt 23 is clean, a light emission amount R1 that provides a certain amount of received light Q1 is obtained and stored in a memory. Thereafter, a light emission amount R2 of the light emitting diode 101 necessary for obtaining the same constant light reception amount Q1 is obtained. The use time of the intermediate transfer belt 23, that is, the rotation time of the intermediate transfer belt 23 is obtained from the obtained light emission amounts R1 and R2 and the data of FIG. 7 stored in the memory.

  For example, the light emission amount R2 of the light emitting diode 101 necessary for obtaining a constant light reception amount Q1 may be adjusted by, for example, the variable resistor VR1 of FIG. In this case, the variable resistor VR1 is adjusted to 0 to 256 levels, for example. Then, for example, in FIG. 7, when the step of the amount of emitted light exceeds “100”, for example, it is determined that it cannot be used, and it is determined that replacement or maintenance is necessary.

  The predetermined time or the predetermined number of sheets may be a value that can be changed in a timely manner in the image forming apparatus 1.

  In still another example of the method for detecting the surface state of the intermediate transfer belt 23, as shown in FIG. 8, the toner adhesion amount is detected for the toner pattern, and the output signal S1 of the P-wave photodiode 102 from the toner pattern is detected. It is also possible to detect the surface state of the intermediate transfer belt 23 based on the above.

  Further, when there is a scratch or filming on the surface of the intermediate transfer belt 23, when the toner adhesion amount is small, the influence is exerted and the output signal S1 of the P-wave photodiode 102 is lowered. It is possible to detect the surface state of the intermediate transfer belt 23 based on various characteristics.

  As described above, according to these embodiments, the life of a part such as the intermediate transfer belt 23 is directly detected according to the state of use, so that the optimal part replacement can be performed according to each machine (image forming apparatus). And maintenance can be performed.

  By the way, when the surface of the intermediate transfer belt 23 is scratched or filmed, it becomes impossible to control the toner adhesion amount and the resist control normally, and the intermediate transfer belt 23, the photosensitive drum 41, etc. There is a possibility that the amount of toner adhering to the image carrier becomes very large, causing smearing in the apparatus, and normal printing cannot be performed. Therefore, when scratches or filming occurs, the development bias or exposure amount is limited so that the amount of toner attached to the image carrier does not increase, and replacement or maintenance is performed. In the meantime, control is performed so that the printable state is maintained without breaking the image forming apparatus 1. Operating the image forming apparatus 1 under such restrictions is referred to as a safe mode.

  As a maintenance method when filming occurs, the processing agent attached to the surface of the image carrier or the like is polished so that it can be used as it is.

  Next, an example of the surface state detection process in the image forming apparatus 1 will be described with reference to a flowchart.

  FIG. 10 is a flowchart illustrating an example of surface state detection processing in the image forming apparatus 1.

  In FIG. 10, polarized light is irradiated on the surface of a detection member such as the intermediate transfer belt 23 (# 11), and the reflected light is received by at least two photoelectric sensors via polarizing plates having different polarization axes. (# 12). The output signals of these photoelectric sensors are calculated (# 13). Based on the calculation result, the surface state of the detected member is determined (# 14). If the detected member is in a deteriorated state as a result of the determination (Yes in # 15), it is determined whether the detected member needs to be replaced or maintained (# 16). If replacement or maintenance is necessary, the safe mode is set (# 17), and a display indicating that replacement is necessary is displayed (# 18).

  If it is not in a deteriorated state, it is displayed as normal if necessary (# 20), and if it is in a deteriorated state but not required for replacement or maintenance, it is displayed as necessary if it is in a deteriorated state (# 20). # 19).

  In the above embodiment, the calculation is performed using the output signals S1 and S2 from the two photodiodes 102 and 103, but the calculation is performed using the output signals from three or more photodiodes to detect the surface state. Further, it is possible to judge the deterioration state and judge the scratch or filming state.

  In the embodiment described above, the image forming apparatus 1 is a tandem-type full-color electrophotographic apparatus using the intermediate transfer belt 23, but is not limited to the intermediate transfer belt 23 as an image carrier, and the photosensitive drum 41. Others may also be used.

  Further, the present invention can detect the surface states of various detection members other than the image carrier. For example, the detected member may be a rotating body such as a paper feed roller, a transfer roller, and a fixing roller, or various other replacement parts in addition to the image carrier. Although the case where the irradiation light is infrared light has been described, the same effect can be obtained even when visible light having a wavelength reflected by the color toner is used.

  In the embodiment described above, the structure, configuration, circuit, shape, size, number, material, processing content or processing order of the control unit 21, the IDC sensor 33, or the entire image forming apparatus 1 or each unit are as follows. It can change suitably according to the meaning of invention.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the arrangement | positioning state of an IDC sensor. It is a perspective view which shows a mode that the detection of a resist pattern is performed. FIG. 4 is a block diagram illustrating a functional configuration for detecting a surface state of an intermediate transfer belt. FIG. 4 is a diagram illustrating a change state of a P wave and an S wave according to a surface state of an intermediate transfer belt. FIG. 6 is a diagram illustrating a state in which detection characteristics change according to a surface state of an intermediate transfer belt. It is a figure which shows the example of the time-dependent change of the emitted light amount for obtaining a fixed light reception amount. It is a figure which shows the relationship between the toner adhesion amount and the detection characteristic of P wave. It is a figure which shows the spectral reflectance characteristic of the toner of each color. It is a flowchart which shows the example of a surface state detection process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 21 Control part 23 Intermediate transfer belt (Image carrier, detected member)
33 IDC sensor 101 Light-emitting diode (light-emitting unit)
102 Photodiode (first photoelectric sensor)
103 Photodiode (second photoelectric sensor)
104 Polarizing plate (light emitting part)
105 Polarizing plate (first polarizing plate)
106 Polarizing plate (second polarizing plate)
113 Calculation unit 114 Surface state determination unit (determination unit)
115 Safe mode setting part (setting part)

Claims (10)

Irradiate the surface of the member to be detected with polarized light,
The reflected light is received by the first photoelectric sensor via the first polarizing plate having the polarization axis in the first direction, and the second polarization axis having a second direction different from the first direction is received. Light is received by the second photoelectric sensor through the polarizing plate of 2,
Performing a calculation based on both the output signal of the first photoelectric sensor and the output signal of the second photoelectric sensor, and detecting the surface state of the detected member based on the calculation result;
A method for detecting a surface state of a member to be detected. A method for detecting a surface state of an image carrier in an image forming apparatus,
Irradiate the surface of the image carrier with polarized light,
The reflected light is received by the first photoelectric sensor via the first polarizing plate having the polarization axis in the first direction, and the second polarization axis having a second direction different from the first direction is received. Light is received by the second photoelectric sensor through the polarizing plate of 2,
Performing a calculation based on both the output signal of the first photoelectric sensor and the output signal of the second photoelectric sensor, and detecting the surface state of the image carrier based on the calculation result;
A method for detecting the surface state of an image carrier. Detecting the surface state of the image carrier based on the calculation result, thereby determining the deterioration state of the image carrier;
The method for detecting the surface state of an image carrier according to claim 2. According to the determination of the deterioration state, it is determined whether the image carrier needs to be replaced or maintained.
The method for detecting the surface state of an image carrier according to claim 3. When it is determined that the image carrier needs to be replaced or maintained, the image carrier should not be damaged until the image carrier is replaced or maintained. Set safe mode,
The method for detecting the surface state of an image carrier according to claim 4. A light emitting unit that irradiates the surface of the member to be detected with polarized light; and
A first photoelectric sensor that receives light reflected by the surface of the member to be detected by the light emitted from the light emitting unit via a first polarizing plate having a polarization axis in a first direction;
A second photoelectric sensor that receives the reflected light through a second polarizing plate having a polarization axis in a second direction different from the first direction;
A determination unit that performs an operation based on both the output signal of the first photoelectric sensor and the output signal of the second photoelectric sensor and determines the surface state of the detected member based on the operation result;
An apparatus for detecting a surface state of a member to be detected, comprising: An image forming apparatus configured to transfer a toner image formed in an electrophotographic process to a transfer material via an image carrier,
A light emitting unit for irradiating the surface of the image carrier with polarized light;
A first photoelectric sensor that receives light reflected by the surface of the image carrier of the light emitted from the light emitting unit via a first polarizing plate having a polarization axis in a first direction;
A second photoelectric sensor that receives the reflected light through a second polarizing plate having a polarization axis in a second direction different from the first direction;
A determination unit that performs an operation based on both the output signal of the first photoelectric sensor and the output signal of the second photoelectric sensor and determines the surface state of the image carrier based on the operation result;
An image forming apparatus comprising: The determination unit determines a deterioration state of the image carrier;
The image forming apparatus according to claim 7. The determination unit determines the necessity of replacement of the image carrier or the necessity of maintenance according to the determination of the deterioration state.
The image forming apparatus according to claim 8. When it is determined that the image carrier needs to be replaced or maintained, the image carrier should not be damaged until the image carrier is replaced or maintained. Having a setting part for setting the safe mode;
The image forming apparatus according to claim 9.